Glass, polymer or ceramic articles with complex cross-sectional structures may be used in a variety of applications. For example, glass or polymer microstructured optical fiber may be drawn from a microstructured optical fiber preform which may generally comprise a central microstructured region surrounded by a cladding or relatively thick-walled solid sleeve. The microstructured region may surround a central core which provides the light guiding characteristics of fiber drawn from the preform. The microstructured region may be formed with a plurality of passages or air holes such that the microstructured region has a very high open to solid ratio (e.g., the microstructured optical fiber is “air filled”). The microstructured region of the preform may be connected to the thick-walled sleeve and the core with a web of thin-walled struts which suspend the microstructured region between the core and the solid sleeve. Accordingly, a radial cross section of the microstructured optical fiber may comprise both thick- and thin-walled portions.
Microstructured optical fiber preforms such as those described above may be formed using various techniques such as, for example, a stack and draw technique where a bundle of capillaries are assembled around a glass core and inserted in a glass sleeve which is drawn into the preform. However, it may be desirable to develop alternative methods for forming microstructured optical fiber preforms and other glass, polymer, or ceramic structures.